In a dual turbine power plant approximately one-half the generated steam is used by each turbine to rotate an associated generator for purposes of producing electric power. In a single turbine power generating unit, a malfunction of a turbine or its associated valves, piping or condenser, may render the entire unit unusable until necessary repairs are made. In comparison with a single turbine power plant, a dual turbine plant advantageously offers an increased probability that at least one-half the plant's total power output can be generated, since a malfunction as above-mentioned may require shutting down one turbine-generator, but not both.
During operation of a dual turbine plant it is at times necessary to add or remove from service one turbine-generator, with the other turbine-generator already operating. Generally, such addition or removal desirably is performed while maintaining the on-line status of the turbine-generator that is already operating and with a reduced degree of change, if any, of its power output level. In the event that the steam generator contains superheater and reheater sections to generate superheat and reheat steam for use by the turbines, it is necessary that desired minimum steam flows be maintained through the steam generator sections during addition or removal of a turbine-generator from service, for protection of such sections. When auxiliary steam turbines are connected in the turbine steam paths to drive blowers which circulate coolant gas through a nuclear reactor and the steam generator, then regulation of the pressure of steam at the outlet of the reheater section during such addition or removal, desirably improves control of the speed of the gas blowers, and thus control of the flow rate of coolant gas through the reactor.
A proposed arrangement for loading a turbine-generator in a power plant which includes a gas-cooled nuclear reactor steam supply system relates to single turbine plants. It includes a controller for regulating the pressure of steam at the outlet of the reheater section, but an integral mode used in the controller may limit the performance of such regulation if two of the controllers were to operate simultaneously in a dual turbine plant.
There appears to be a need for apparatus and method of adding or removing from service a turbine-generator while another turbine-generator continues to operate in a dual turbine power plant. Such apparatus and method desirably accomplishes such addition or removal with limited effect, if any, on the power output of the turbine-generator that is already operating. In a dual turbine power plant with a gas-cooled nuclear reactor steam supply system and with auxiliary steam turbines connected in the turbine steam paths for driving coolant gas blowers, such addition or removal is further desirably accomplished while maintaining desired minimum steam flows through the steam generator, and regulating the pressure of reheated steam.
The description of prior art herein is made on good faith and no representation is made that any prior art is considered the best pertaining prior art nor that the interpretation placed on it is unrebuttable.